PIN diode with improved power limiting

Abstract

A PIN diode comprising an N-type substrate comprising a cathode of the PIN diode and having an intrinsic layer disposed upon the N-type substrate and having a top surface a P-type material disposed upon the top surface of the intrinsic layer comprising an anode of the PIN diode and a N-type material disposed over the sidewall of the cathode and over the sidewall and a portion of the top surface of the intrinsic material that is not occupied by the anode, wherein a horizontal gap is defined between the anode and the cathode through the intrinsic material, the gap being variable in width and/or the horizontal gap is less than the thickness of the intrinsic layer.

1. A PIN diode comprising:
 an N-type substrate comprising a cathode of the PIN diode and having a sidewall; 
 an intrinsic material disposed upon the N-type substrate and having a top surface and a sidewall; 
 a P-type material disposed upon the top surface of the intrinsic layer comprising an anode of the PIN diode; and 
 a N-type material disposed over the sidewall of the cathode and over the sidewall and a portion of the top surface of the intrinsic material that is not occupied by the anode; 
 wherein a horizontal gap is defined between the anode and the cathode through the intrinsic material, the gap being variable in width. 
 
     
     
       2. The PIN diode of  claim 1  wherein the anode is an island of P-type material surrounded by the N-type material on the top surface of the intrinsic material. 
     
     
       3. The PIN diode of  claim 2  wherein the anode is circular in horizontal cross section and the N-type material has an inner circumference on the top surface of the intrinsic material that is circular in cross section, and wherein the circular anode and circular inner circumference of the N-type material are non-concentric. 
     
     
       4. The PIN diode of  claim 3  further comprising an insulating layer disposed over the N-type substrate, the intrinsic material and the N-type material and defining a window therein through which the anode is exposed. 
     
     
       5. The PIN diode of  claim 4  wherein the N-type material comprises an N+ diffusion layer with metal silicide. 
     
     
       6. The PIN diode of  claim 5  wherein the top surface of the intrinsic material is at least twice the area of the anode. 
     
     
       7. The PIN diode of  claim 2  wherein the top surface of the intrinsic material has at least one notch such that the horizontal gap between the N-type material and the anode is smaller in the at least one notch than elsewhere, whereby conduction between the cathode and the anode will begin across the area of the notch before conduction occurs across the rest of the gap. 
     
     
       8. A power limiter circuit comprising the PIN diode of  claim 1 . 
     
     
       9. A circuit comprising the PIN diode of  claim 1  in series with a radio frequency circuit, the PIN diode serving as a protection circuit for the radio frequency circuit by dissipating radio frequency energy when the PIN diode turns on in response to radio frequency energy above a threshold. 
     
     
       10. A PIN diode comprising:
 an N-type substrate having a sidewall; 
 an intrinsic material disposed upon the N-type substrate and having a top surface and a sidewall; 
 a P-type material disposed upon the top surface of the intrinsic layer; and 
 a N-type material disposed over the sidewall of the N-type substrate and over the sidewall and a portion of the top surface of the intrinsic material that is not occupied by the P-type material; 
 wherein a horizontal gap is defined between the P-type material and the N-type substrate through the intrinsic material, the horizontal gap being less than a vertical gap between the P-type material and the N-type substrate defined by the thickness of the intrinsic material and wherein the horizontal gap is less than the vertical gap. 
 
     
     
       11. The PIN diode of  claim 10  wherein the N-type material defines a window on the top surface of the intrinsic material and the P-type material is disposed within the window. 
     
     
       12. The PIN diode of  claim 10  wherein the horizontal gap is variable in width and wherein the vertical gap is greater than the horizontal gap at its smallest. 
     
     
       13. The PIN diode of  claim 10  wherein the horizontal gap is variable in width and wherein the vertical gap is greater than the horizontal gap at its largest. 
     
     
       14. The PIN diode of  claim 11  further comprising an insulation layer disposed upon the intrinsic material in a portion of the window not occupied by the P-type material. 
     
     
       15. The PIN diode of  claim 13  further comprising an encapsulation layer disposed over the N-type substrate, the intrinsic material, the N-type material, and an insulating layer and defining a window therein through which the P-type material is exposed.